Tire structural members fabricated by a tire structural member fabricating method of this kind include a belt member in the form of a cord-reinforced bias sheet. A belt fabricating method disclosed in JP 2001-88225 A forms a belt sheet on a cylindrical drum.
The belt sheet fabricating method disclosed in JP 2001-88225 A delivers strips successively onto a cylindrical drum rotating at a fixed angular velocity by moving a strip feed device at a fixed speed parallel to the axis of the cylindrical drum to attach the strips to the outer surface of the cylindrical drum obliquely to the axis of the cylindrical drum.
As shown in FIG. 8-1, a cylindrical belt structure 01 having a cylindrical shape is formed by thus successively attaching the strips to the cylindrical drum in a circumferential arrangement.
A convex cylindrical belt structure 02 having an outer surface of an outwardly convex cross section as shown in FIG. 8-2 is formed by shaping the cylindrical belt sheet 01. As shown in FIG. 8-2, stitchers 05 are pressed against end parts of the cylindrical belt sheet 01 so as to reduce the diameter of the end parts to form the convex cylindrical belt structure 02 of a shape conforming to the shape of the outer surface of a green tire.
The thus contracted end parts of the convex cylindrical belt structure 02 are creased and the thickness of the end parts varies along the circumference of the convex cylindrical belt structure 02.
The belt sheet fabricating method disclosed in JP 2001-88225 A attaches the strips to the cylindrical drum. If a convex cylindrical drum having a convex outer surface is used instead of the cylindrical drum, a convex cylindrical belt structure similar to the convex cylindrical belt structure 02 shown in FIG. 8-2 can be formed.
In a convex cylindrical drum having a curved outer surface of an outward convex cross section, the diameter of a middle part is greater than that of end parts. Therefore, when a predetermined number of strips are attached successively to the convex cylindrical drum such that middle parts of the strips are in properly adjoining disposition, end parts of the strips are overlapped.
When a predetermined number of strips are attached successively to the convex cylindrical drum such that end parts of the strips are in properly adjoining disposition, gaps are formed between adjacent middle parts of the strips. In either case, a tire structural member having a uniform quality cannot be formed.
The present invention has been made in view of such problems and it is therefore an object of the present invention to provide a tire structural member fabricating method capable of fabricating a tire structural member of a uniform quality by successively arranging a plurality of strips so that adjacent strips are in properly adjoining disposition, and to provide an apparatus for carrying out the method.